import al4th.StdLib.StdIn;
import al4th.StdLib.StdOut;

/*
 * @Author: wanghongfucoder 
 * @Date: 2017-10-12 22:23:22 
 * @Last Modified by: wanghongfucoder
 * @Last Modified time: 2017-10-12 22:26:16
 */

 public class Average{
     public static void main(String[] args) {
         double sum=0.0;
         int cnt=0;
         while(!StdIn.isEmpty()){
            sum+=StdIn.readDouble();
            cnt++;
         }
         double avg=sum/cnt;
         StdOut.printf("Average is %.5f\n",avg);
     }
 }